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January 15, 2002
Underground Fires Menace Land and Climate
By ANDREW C. REVKIN

Fires are burning in thousands of underground coal seams from
Pennsylvania to Mongolia, releasing toxic gases, adding millions of tons
of heat-trapping carbon dioxide to the atmosphere and baking the earth
until vegetation shrivels and the land sinks.

Scientists and government agencies are starting to use heat-sensing
satellites to map the fires and try new ways to extinguish them. But in
many instances particularly in Asia they are so widespread and stubborn
that miners simply work around the flames.

There is geological evidence that grassland and forest fires, lightning
and spontaneous combustion of coal have spawned such fires for hundreds
of thousands of years. In Wyoming and northern China, broad layers of
earth are composed of “clinker,” the brittle baked rock left behind when
subterranean coal burns.

But the frequency of coal fires appears to have risen, experts say, as
mining has exposed more and more deposits around the world to fires,
both natural and set by people, and the oxygen that feeds them.

Increasingly, scientists are saying the problem needs to be more
carefully assessed, both as a potential contributor to global warming
and source of toxic air pollution.

A 1999 report by the Clean Coal Center of the International Energy
Agency concluded that the biggest coal fires, in China and India
particularly, “make a significant global impact.”

“These fires are obviously pumping all this noxious material into the
air,” said Dr. Glenn B. Stracher, a geologist and expert on mine fires
at East Georgia College in Swainsboro, Ga. “That’s got to be having some
effects, but no one has been studying it.”

The coal fires are similar to those that smoldered for months beneath
the wreckage of the World Trade Center, in that they involve buried
fuels and are sustained and intensified by slight drafts of air and heat
locked into surrounding rubble or rock. Geologists and engineers who
have studied coal fires offered their expertise and specialized
equipment like firefighting foams to emergency officials in Lower
Manhattan. But firefighters at the scene stuck mainly with the simplest
method: pouring endless streams of water on the wreckage as work crews
slowly removed layers of debris.

Many coal fires start spontaneously, when pyrite and other reactive
minerals in coal are exposed to oxygen. They begin to release heat,
which, if not dissipated by air currents, builds until the coal itself
ignites.

In Indonesia, hundreds of coal fires erupted deep in the rain forests
when forest fires spread during an extreme drought in 1997 and scorched
exposed coal seams.

Alfred E. Whitehouse, a fire expert for the federal Office of Surface
Mining, now assigned to Indonesia, said there were 700 such fires just
in East Kalimantan, on the island of Borneo. Some were extinguished by
crews using hand pumps and picks to isolate the hot spots. But many are
still burning, he said.

The fires persist as long as there is the right mix of fuel, oxygen and
heat.

Sometimes, that can be a very long time. One fire eating deep into an
Australian peak called Burning Mountain is believed to have been going
strong for 2,000 years. The mountain has often been mistaken for a
simmering volcano by passers-by, although Australia has no volcanic
activity.

In the United States, a common cause of such fires has been the burning
of trash dumped into abandoned mines.

That is how the coal fire most familiar to many Americans started 40
years ago, in Centralia, a town in the anthracite region of eastern
Pennsylvania. Smoldering trash in a dump ignited a coal seam. The fire
steadily crept through abandoned mine tunnels, forcing the federal
government by 1984 to evict residents and eventually pay $40 million to
buy damaged land.

Centralia briefly gained national notoriety, then faded away. Its
population shrank from 1,100 to 40. Smoke and steam now rise from
overgrown backyards and cracked, sunken streets, marking the path of
subterranean fires that continue to consume buried coal. Geologists say
it could burn for another hundred years.

But Centralia’s is just one of dozens of fires that smolder unchecked in
old mines and coal seams around the country. The federal Office of
Surface Mining has tallied nearly $1 billion in accumulated costs from
coal fires, primarily in Pennsylvania, West Virginia, Utah, Colorado,
Kentucky and Wyoming.

And the coal fires in the United States are negligible compared with
those overseas. In China’s rich northern coal belt, hundreds of
underground fires are burning upward of 200 million tons of coal each
year, about 20 percent of the nation’s annual production. The fires
produce nearly as much carbon dioxide, the main gas linked to global
warming, as is emitted each year by all the cars and small trucks in the
United States.

Only in the last few years have scientists begun a concerted effort to
map and monitor coal fires around the world and calculate how much
pollution they are producing.

For the moment, the total is anyone’s guess, said Dr. Anupma Prakash, a
geological mapping expert at the International Institute for Aerospace
Survey and Earth Sciences in the Netherlands. Dr. Prakash has been
developing ways to integrate maps of the heat of the earth’s surface
generated by satellites with geological maps to track coal fires in
northern China.

Often, a deep coal fire raises the surface temperatures by only a few
degrees, even though the heat in the middle of the fire can easily
exceed 1,000 degrees. But that subtle signal is enough to show up from
space, particularly when other clues about coal deposits are combined
with the heat data, Dr. Prakash said.

The team from her institute, together with Chinese geologists, recently
generated a map of China’s coal fires that showed a constellation of
glowing orange spots spread across the country’s northern coal belt,
which spans 3,000 miles and is 400 miles wide.

One goal, Dr. Prakash said, is to monitor the region continually from
space, so spots that are growing warmer indicating intensifying fires
can be attacked by firefighters before the fires grow to the point where
they cannot not be stopped.

“The important thing is to detect the rising heat anomalies ahead of
time,” she said.

Once they get going, these buried fires are very hard to stop, said
Stanley R. Michalski, a senior staff geologist at GAI Consultants, a
firm in Monroeville, Pa., that has for more than 20 years studied fires
and drawn unp firefighting plans from India to Centralia.

The coal beds in Pennsylvania, Mr. Michalski said, tend to generate
particularly persistent fires because the corrugated terrain there has
many separate, narrow coal seams that reach the surface, and the ground
is heavily fractured, allowing ample oxygen to reach the coal. Many
parts of the state, like the foundation of Centralia, are also riddled
with old abandoned tunnels that carry air into the coal layers and
expose broad surfaces of coal to heat.

For many years, engineers and scientists have been experimenting with a
variety of ways to extinguish or control the fires. Some small fires
have been snuffed by drilling holes and pumping in inert gases or foams
that stifle flames. Others have been flooded by damming surface streams
and creating lakes over the burning coal.

Some fires have been controlled by excavating deep trenches that cut off
the fires the same way a fire break in a woodland can stop a forest fire
from spreading.

But in most cases the costs of such efforts outweigh the benefits. That
was why Centralia picked up and moved and why another Pennsylvania
community, Youngstown, may suffer the same fate.

Overseas, however, some of the fires are in densely populated regions
where hundreds of thousands of poor people live on the edges of open
pits that fume and flame.

In many such places, the mining industry has simply adapted to the
situation, working in and around the burning rock.

Parts of one of India’s most important coal fields, the Jharia mining
complex, which is rich in low-sulfur coal used to produce coke for steel
mills, have been on fire since 1916. In many places, the walls of
open-pit mines glow and hiss like lava flows.

The region’s 150,000 miners, truck drivers, train loaders and other
workers toil stolidly against a constant backdrop of orange flames and
brown smoke.

But the fires are far more than an inconvenience. On Sept. 10, 1995, the
walls of one mine complex collapsed after being progressively weakened
by fires. Water from a nearby canal poured in and flooded the pits and
tunnels, killing more than 60 miners.

The population around the Jharia mines has grown from half a million to
1.1 million since the early 1980’s, said Dr. Prakash, whose doctoral
thesis was an analysis of the fires there.

Mr. Michalski has also surveyed the Jharia fires several times since the
early 1990’s, when the World Bank hired his company to assess what to
do.

A plan was drawn up to modify the mining operations and constrain the
fires. But the bank never released the money, Mr. Michalski said.

He conceded that it would take an awful lot of money. “It’s a loss of a
valuable resource, it’s an environmental disaster, it’s devastating,”
Mr. Michalski said. “But this fire is so complicated and so widespread
that India could not really afford to extinguish it.”

In the meantime, the fires there still burn, and residents and
mineworkers continue to adapt.

In places where the ground cracks and slumps and smokes, people simply
dismantle their mud-brick homes and move them somewhere else.